Firstly you've to complete an online application form which consists of brief information about yourself as well as a a type of questionnaire which they use to assess your suitability for the role. This questionnaire consists of given scenarios, with multiple choice answers. You must select the answer according to what you would do in the given scenario.
If your application is successful you will be contacted and invited to the 'Asda Magic Day'. This is no more than 2 hours long and consists of a tour of the store, a group activity, training including watching videos about matters such as health and safety, and finally a 1-1 interview.